The present invention relates to snack foods. More particularly, it relates to snack foods comprising dehydrated potato and to their manufacture.
Snack foods made from potato are well known, and are available in a wide range of shapes and flavours. One form of snack food derived from potatoes is the potato crisp, known in the USA as the potato chip, which is commonly prepared by slicing potatoes and frying the slices. It is also known to manufacture snack foods by preparing a dough from dehydrated potato material, forming that dough into pieces of desired shape, for example by sheeting and subsequently cutting the dough sheet, or by extrusion, and then frying or baking the shaped dough pieces. The manufacture of snack foods from dehydrated potato material has the advantages that it is easier to maintain consistency of the product throughout the year in spite of seasonal variations of potatoes and that a wider variety of shapes can be made relatively easily. Potato flakes and potato granules are forms of dehydrated potato which are particularly well suited for use in the manufacture of snack foods.
U.S. Pat. No. 5,429,834 describes preparation of snack products from a dough based on ingredients such as potatoes which are high in starch but lack gluten. It is suggested that the elasticity of such doughs may be increased by adding a pregelatinised waxy starch such as pregelatinised waxy maize starch.
Despite the great variety of potato snack foods now available there remains a demand for improved snack foods, for example, potato snack foods having an improved texture.
The present invention provides a snack food comprising high amylopectin potato flakes and/or high amylopectin potato granules.
The starch of plants commonly consists of two types of glucose polymer, amylopectin and amylose. Amylopectin is highly branched and has a very high degree of polymerisation, for example, about 2,000,000. Amylose is, in contrast, linear or lightly branched and has a lower degree of polymerisation of about 1000 to 5000. Those differences in structure lead to significant differences in properties between amylopectin and amylose. For example, amylopectin is highly soluble in water and forms clear gels of reasonably stable viscosity. It is believed that that is because its high degree of branching prevents ordering of the molecules in solution. In contrast, amylose quickly crystallises out of aqueous solution. It follows that the properties of a starch from a given source will be dependent on the ratio of amylopectin to amylose.
There exist natural varieties of some cereals such as maize and rice in which the starch is substantially all amylopectin with less than 5%, and usually less than 2%, amylose. Maize of which the starch consists of 100% amylopectin is known as waxy maize and the starch from waxy maize has since the 1940s found a number of applications, principally in paper manufacture but also as a thickener in foods. EP 0,314,320 A1 discloses snack foods which comprise waxy maize masa and which are stated to have a different texture from equivalent foods made with dent corn. Nevertheless, waxy maize material other than isolated starch has not found wide application in snack foods.
The starch of potatoes typically consists of approximately 20% amylose and 80% amylopectin, although that ratio varies slightly according to the variety of potato and growing conditions. References herein to a normal amylopectin content in potato starch are intended to imply an amylopectin content of about 80%±3%, dry weight basis. At present, there are no known natural varieties of potato in which the starch consists substantially entirely of amylopectin. For a number of years, however, there have been available genetically modified potato plants which produce potatoes in which substantially all of the starch consists of amylopectin.
EP 0,703,314 A and the references therein describe genetically modified amylopectin potatoes (known as “waxy potatoes”) and the use of the separated amylopectin potato starch from those potatoes as a wet-end additive in paper making. EP 0,799,837 A discloses the preparation of an aqueous composition comprising amylopectin potato starch in combination with an emulsifier and suggests that such compositions may find application in products having a gel structure, for example, food products such as puddings, jellies and custard or in foods having the form of viscous liquids such as sauces, creams and soups.
EP 0,703,314A and EP 0,799,837A describe applications of the starch isolated from the waxy potatoes. In contrast, the present invention is concerned, not with the separated starch, but instead with the use of whole potato (less the skin) in the form of potato flakes and/or granules.